14 



Elementary Botany 



protoplasm. They are insoluble in water, but break up in a 

 peculiar manner so as to appear to be composed of several 

 layers. 



Aleurone Grains are minute rounded grains found in the 

 cells of many seeds just before ripening. They often contain 

 crystalloids. They are soluble in caustic potash. They are 

 often oily, and appear to be used as food reservoirs by the plant. 



Fig. 15.— Cells of cotyledon of Fiswn 

 sativum. Pea. St, starch granules with 

 central hilum and concentrated striee ; a, 

 granules of aleurone ; i, intercellular spaces 

 (After Sachs.) 



Fig. 16.— Sphere crystals of 

 inuline in a parenchymatous 

 cell from a tuber of the 

 Dahlia preserved in alcohol, 

 after addition of nitiic acid. 



Inuline is a peculiar substance found in the roots of 

 Compositse, and now and then in stems. It is very closely 

 related to starch and sugar, and in the living plant is only found 

 in solution in the sap ; but by the addition of alcohol or 

 glycerine it separates out, either in a frothy condition or as 

 beautiful spherical masses known as sphere crystals. 



